In navigation with an airborne, marine or land vessel, the pilot or other control person usually relies upon several parameters to determine the location, bearing, elevation and other indicia that indicate where the vessel is relative to the chosen path. In airborne and marine vessels, this normally requires provision of one monitor or screen to display each relevant parameter in analog form. The pilot must read, understand and coordinate the information displayed on each monitor. This usually requires that the pilot's eyes move intermittently from one monitor to the next monitor to visibly sense this information.
Some workers in other fields have provided relevant information on adjacent screens or screen sections. U.S. Pat. No. 3,778,601, issued to Brock et al, discloses an aircraft navigation system for display or indication of track angle or cross track error in the angle. Computed aircraft location coordinates are combined to provide along-track distance and across-track error in the representation of FIG. 1 of this patent. However, no indication is given of how two such indicia could be combined and displayed on a single screen.
Brinker et al disclose a bearing display for a plurality of targets relative to a pursuit craft, such as a water-borne or airborne craft in U.S. Pat. No. 3,864,555. A movable dial displays bearing of the craft in degrees, is controlled by a gyro on the craft, and includes a circular array of lights surrounding the center of the dial. Each light subtends an angle of a few degrees relative to the dial center. If a the system determines that one or more targets is positioned within an angular sector defined by one of these lights, that light is activated. Craft bearing and angular location of one or more targets relative to the craft are displayed on a single instrument.
A navigational computer that provides displays of aircraft bearing angle and aircraft speed, or other equivalent information, is disclosed by Ferguson in U.S. Pat. No. 3,875,405. In one embodiment, the north-directed component and east-directed component of an aircraft velocity vector are separately displayed on two adjacent disks, with the two disks having complementary opaque half-disks. The disk diameter separating the opaque half-disk from the visible half-disk on each disk moves with change in aircraft bearing.
In U.S. Pat. No. 4,112,423, Bertolasi discloses a dual screen data monitor that can display 160 alphanumeric characters, rather than the standard 80 characters, in a single line. Much of the emphasis here is on synchronism of timing of the displays across the "fold" of the two screens, and no extension to non-alphanumeric displays is disclosed. Static images are displayed.
Lewis, in U.S. Pat. No. 4,167,735, discloses an aircraft orientation system that measures and displays the "crab angle" (yaw angle relative to aircraft ground velocity vector) of an aircraft during a landing approach. Two Doppler radar units, facing each other on two sides of a landing strip center line, transmit timed pulses and receive return pulses indicating the angular orientation and velocity of the aircraft center line relative to the landing strip center line. Graphic display of this information is not discussed.
A torpedo steering control system for or a self-controlled pursuit torpedo is disclosed in U.S. Pat. No. 4,323,025, issued to Fisher et al. In one embodiment, the system quantitatively measures and uses torpedo depth, rate of change of depth and rate of change of torpedo pitch angle, to control the velocity vector in a search-and-destroy pattern, directed at an underwater object such as a moving submarine.
U.S. Pat. No. 4,706,199, issued to Guerin, discloses a moving map display that provides differently shaded or colored regions corresponding to different topographical heights of the terrain over which an aircraft flies. The topographical relief information is pro-loaded and is combined with the sensed present location and present altitude of the aircraft on a single screen. The present height of the aircraft relative to the ground directly below is also displayed.
Van Helsdingen et al disclose a system for navigating and displaying, present location of a free ranging vehicle in U.S. Pat. No. 4,847,773. The region over which the vehicle can move is defined by a two-dimensional grid of reflective markers that indicates obstacles to be avoided and a preferred path to be followed. The system can compute and separately display cumulative distance traveled, present location and present bearing within the grid.
A navigation system fort a vehicle and coordinated, changeable map display is disclosed by Ohe in U.S. Pat. No. 4,964,052. The navigation system senses the present location, present bearing and present speed relative to a two-dimensional grid and can display an icon representing the estimated vehicle location on an appropriate map showing all navigable roads, depending upon vehicle location.
In U.S. Pat. No. 4,974,196, Iwami et al disclose a multi-window screen for displaying the results of several data processing procedures. Simultaneous window views of a bar chart and a table may be displayed, for example, upon command. However, coordination and display of two or more related variables in a single window is not disclosed.
Lord discloses a remote control system for helicopter flight training in U.S. Pat. No. 5,015,187. The remotely controlled helicopter has a video link to the control unit that displays the terrain seen in the forward direction of the craft and separately displays, simultaneously on a single screen (1) craft airspeed, (2) craft pitch or direction and (3) relative wind direction. No indication is given as to how relative location of the helicopter could be included on the screen display.
A two-dimensional display to appear on a helmet of an aircraft pilot as the aircraft changes location and angular orientation is disclosed in U.S. Pat. No. 5,015,188, issued to Pellosie et al. The display can be changed by the pilot to any of a designated plurality of two-dimensional views of the three-dimensional environment in which the aircraft operates, including a view to the front, view to the rear and one or more lateral views. The view of any other object in the scene automatically changes as the scene perspective changes. The displayed image is projected on a visually perceptible surface that is part of the helmet, to be viewed by the pilot as the aircraft moves.
In U.S. Pat. No. 5,018,076, Johary et al disclose a dual flat panel display system that provides two separately controllable images, which may be identical if desired. Static or dynamic images can be displayed. One display panel image is written and displayed while information for the other panel is being read from the same or another set of memory addresses.
A primary flight display system in which two measurements, coarse and fine, of a single flight path variable are separately displayed on a single display panel is disclosed in U.S. Pat. No. 5,136,301, issued to Bechtold et al. However, only one basic variable, elevation, is disclosed, and no comparison of present and ideal path values is presented.
In U.S. Pat. No. 5,153,936, issued to Morris et al, a data processing system is disclosed that processes, displays and/or prints document digital images at two or more different resolutions, depending upon the nature of the image and upon any image compression used. The images are static and are scanned in and stored before display thereof.
None of these references displays two or more closely related variable values, such as deviation of location, deviation of elevation, and deviation bearing angle of a vessel from a preselected path, on a single monitor in such a way that the variable values can be easily coordinated. What is needed is a system that displays two or more closely related variables or path deviations on a single monitor in such manner that the variables values can be easily coordinated, appropriate corrective action can be taken, and the variable values can be continually monitored as the correction is implemented.